function [ status ] = mx_eyelink_event_data_flags( void )
%MX_EYELINK_EVENT_DATA_FLAGS Returns the event data content flags.
%
% Remarks:
% This will be 0 if the data being read from queue is not in a block with events.
% Returns:
% Event data content flags: EVENT_VELOCITY if has velocity data. EVENT_PUPILSIZE 
% if has pupil size data. EVENT_GAZERES if has gaze resolution. EVENT_STATUS 
% if has status flags. EVENT_GAZEXY if has gaze xy position. EVENT_HREFXY if 
% has head-ref xy position. EVENT_PUPILXY if has pupil xy position. FIX_AVG_ONLY
% if only avg. data to fixation events. START_TIME_ONLY if only start-time in
% start events. PARSEDBY_GAZE if how events were generated. PARSEDBY_HREF. 
% PARSEDBY_PUPIL.
%
% EVENT_VELOCITY  0x8000  /*!< has velocity data */
% EVENT_PUPILSIZE 0x4000  /*!< has pupil size data */
% EVENT_GAZERES   0x2000  /*!< has gaze resolution */
% EVENT_STATUS    0x1000  /*!< has status flags */
%
% EVENT_GAZEXY    0x0400  /*!< has gaze xy position */
% EVENT_HREFXY    0x0200  /*!< has head-ref xy position */
% EVENT_PUPILXY   0x0100  /*!< has pupil xy position */
%
% FIX_AVG_ONLY    0x0008  /*!< only avg. data to fixation evts */
% START_TIME_ONLY 0x0004  /*!< only start-time in start events */
%
% PARSEDBY_GAZE   0x00C0  /*!< events were generated using GAZE*/
% PARSEDBY_HREF   0x0080  /*!< events were generated using HREF*/
% PARSEDBY_PUPIL  0x0040  /*!< events were generated using PUPIL*/
%
%----------------------------------------------------------------------------
% Copyright Eduardo Aponte 2013
% aponteeduardo@gmail.com